Not getting stream of data in angular5 using pptxGenjs library

I am trying to add images in ppt file using pptxGenjs in angular5.

I am able to get the file with content, but I want to get the ppt file data in base64 or any other output format, but I am getting only the filename in data.

            const pptx = new pptGen();
            const slide = pptx.addNewSlide();
            // slide.addImage({ data: 'image/png;base64, ' + b64Data + '', x: 1, y: 2, w: 3, h: 3 })
            slide.addImage({ path: '/assets/mean.jpg', x: 1, y: 2, w: 3, h: 3 })
            slide.addText('Image Path!', { x: 1.5, y: 1.5, font_size: 18, color: '363636' });
            pptx.save('jszip', this.getData, 'base64');
            // pptx.save('http', this.getData); // I tried this also

            getData = () => {
               console.log(data);
            }

How to get the stream of ppt file data? It would very helpful If I get any help on this.

I resolved my problem by making some changes in the library. the changes which I made is:

File: pptxgen.js
go to line no 1823 and replace the code:
// original code
zip.generateAsync({type:'blob'}).then(function(content){ writeFileToBrowser(strExportName, content); });

// code to replace
    zip.generateAsync({type:'blob'})
    .then(function(content){
     gObjPptx.saveCallback(content);
     // writeFileToBrowser(strExportName, content);
    });